Supercharger control device for internal combustion engine

Abstract

A turbocharging system of an internal combustion engine includes compressor of a turbocharger disposed on an intake passage of an internal combustion engine and a turbine disposed on an exhaust passage of the internal combustion engine. A bypass passage connects an upstream side and a downstream side of the turbine in the exhaust passage together. A wastegate valve, which is disposed on the bypass passage, opens and closes the bypass passage according to turbocharging pressure of the compressor. An accumulator, which accumulates exhaust gas pressure, is connected to a downstream side of the wastegate valve in the bypass passage. A recirculation passage connects the accumulator and an upstream side of the turbine together, and a recirculation valve, which opens and closes the recirculation passage based on an output request, is deposed on the recirculation passage.

The invention claimed is: 
     
       1. A turbocharging control apparatus configured to control operation of a turbocharger having a compressor disposed on an intake passage of an internal combustion engine and a turbine disposed on an exhaust passage of the internal combustion engine, comprising:
 a bypass passage connecting an upstream side and a downstream side of the turbine in the exhaust passage together; 
 a wastegate valve disposed on the bypass passage, wherein the wastegate value is configured to open and close the bypass passage according to turbocharging pressure of the compressor; 
 an accumulator connected to a downstream side of the wastegate valve in the bypass passage, wherein the accumulator is configured to accumulate exhaust gas pressure; 
 a recirculation passage connecting the accumulator and an upstream side of the turbine; and 
 a recirculation valve disposed on the recirculation passage, wherein the recirculation valve opens and closes the recirculation passage in accordance with an output request. 
 
     
     
       2. The turbocharging control apparatus according to  claim 1 , further comprising:
 a three-way valve disposed on the bypass passage downstream of the turbine; and 
 an accumulation passage connecting the accumulator and the three-way valve together, 
 wherein the three-way valve is configured to bring an upstream side of the turbine into one of the accumulation passage and a downstream side of the turbine according to internal pressure of the accumulator. 
 
     
     
       3. The turbocharging control apparatus according to  claim 2 , further comprising:
 a pilot passage through which internal pressure of the accumulator is transmitted to the three-way valve, 
 wherein when the internal pressure introduced from the pilot passage is not less than a predetermined pressure the three-way valve brings the upstream side of the turbine into one the downstream side of the turbine, and when the internal pressure introduced from the pilot passage is less than a predetermined pressure the three-way valve brings the upstream side of the turbine into the accumulation passage. 
 
     
     
       4. The turbocharging control apparatus according to  claim 2 , further comprising:
 a check valve disposed on the accumulation passage. 
 
     
     
       5. The turbocharging control apparatus according to  claim 3 , further comprising:
 a check valve disposed on the accumulation passage. 
 
     
     
       6. The turbocharging control apparatus according to  claim 1 , further comprising:
 an electronic control unit configured to control a degree of opening of the recirculation valve, 
 wherein when the turbocharging pressure is less than a predetermine pressure, and the output request is not less than a predetermined amount the electronic control unit increases the degree of opening of the recirculation valve, and when the turbocharging pressure is not less than the predetermine pressure and the output request is less than the predetermined amount the electronic control unit decreases the degree of opening of said recirculation valve.